The CUV156 study will evaluate the safety of afamelanotide in XP-C patients, as well as the drug's ability to assist reparative processes following ultraviolet (UV) provoked DNA damage of the skin. It will assess whether SCENESSE® increases the amount of UV light needed to cause DNA damage of skin cells, as well as the extent of skin repair before and after treatment.

Inclusion Criteria:

• Male or female patient with a molecular-genetically confirmed diagnosis of XP-C;
• Aged 18-75 years.

Exclusion Criteria:

• Known allergy to afamelanotide or the polymer contained in the implant;
• Presence of severe hepatic disease or hepatic impairment;
• Renal impairment;
• Any other medical condition which may interfere with the study protocol;
• Female who is pregnant (confirmed by positive urine beta-Human chorionic gonadotropin pregnancy test) or lactating;
• Females of child-bearing potential (pre-menopausal, not surgically sterile) not using highly effective contraceptive measures with a failure rate of less than 1% per year when used consistently and correctly (i.e. oral contraceptives, intrauterine device) or a life-style excluding pregnancy, for up to three months after the last implant administration;
• Sexually active man with a partner of child-bearing potential (pre-menopausal, not surgically sterile) who is not using highly effective contraceptive measures, as described above;
• Use of any other prior and concomitant therapy which may interfere with the objective of the study, within 30 days prior to the Screening visit;
• Participation in a clinical trial for an investigational agent within 30 days prior to the Screening visit.